Production of hydrocarbons from oil shale



A. P. BJERREGAARD PRODUCTION OF HYDROCARBONS FROM OIL SHALE Filed NOV. l18, 1924 Oct. 22, 1929.

mw. NT Nk *Sw QSQQ |621 WGS v@ so Imw Patented Oct. 22, 1929 UNITED STATES PATENT OFFICE 'AUGUST P. BJERREGAARD, OF OKMULGEE, OKLAHOMA, .ASSIGNOR TO DOI-IERTY RE- SEARCH COMPANY, OF NEW YORK, N. Y., .A CORPORATION OF DELAWARE PRODUCTION OF HYDROCARBONS FROM OIL SHALE Application led November 18, 1924. Serial No. 750,574.

The present invention relates to the production of hydrocarbons from oil shale.

One o f the objects of the present invention is to provide a process for retorting oil shale having a high efficiency, and requiring relatively inexpensive apparatus.

Another object of the present invent/ion is to provide a process for obtaining a high percentage hydrocarbon yield from oil shale ata comparatively low cost.

The no'vel features of the present invention are pointed out with particularity in the appended claim. The invention itself however with further objects and advantages thereof will best be understood from the following description taken in connec tion with the accompanying drawing, in which The ligure is an elevation diagrammatic in character, of an apparatus adapted' to operate according to the process of the present invention, parts being shown in section and parts being broken away for purposes of illustration. t

In the drawing 10 is a hopper for receiving oil shale to be treated, shale supplied to hopper 10 having been previously treated to produce suitable sizes. The shale passes downwardly from hopper 10 through a chute 12, the rate of feed from the hopper being regulated by a valve 14 or other suitable feeding mechanism as desired. As illustrated, chute 12 is arranged vertically and the lower end thereof delivers into an inclined chute 16 -arranged to deliver the shale into the. upper end of an inclined rotary lagged retort 18. The oil shale `is fed forwardly and downwardly through the retort 18 and while it is in, the retort it is treated with aY countercurrent stream of hot producer gas. The producer gas for-treat ing the shale in retort 18 is introduced into the lower end of the retort; that is to say, the end opposite the chute 16, the shale which has been longest in the retort 18 thus coming in contact with the hottest gas and the shale just entering retort 18 from the chute 16 encountering the coolest gas.

According to the ,present invention, no heat is supplied to the exterior ofthe retort 18, and no heat is supplied to the shale in retort 18 except by the producer gas flowing through the interior of the retort so that the shale/in retort 18 is brought gradually to the point at which decomposition of the hydrocarbons in the shale is produced. Moreover, owing to the agitation of the shale in the rotary retort and the fact that heat is supplied to the shale solely by the hot gases, the stream of shale is heated'very.

uniformly. The temperature of the zone in the retort 18 in which the hydrocarbons are given oil' is fixed and controlled by the temperature of the retort gases, the rate of 'feed of the shale, and the degree of insulation 'of the retort 18 against a loss of heat. Owingv to the conditions just mentioned, thereis ractically no chance for any of the shale t`o ecome heated to the point at which the hydrocarbons given off by the shale are cracked as they are given off. Moreover, the hot producer gases have a high absorptive capacity .for the hydrocarbon vapors and gases and greedily absorb them, and

sweep them from the point where they are formed toward the cooler yport-ions of the retort. There is --therefore no opportunity for hydrocarbons once freed from the shale to be subjected to secondary cracking. On account of this absence of cracking in the apparatus and process according to the pres- -ent invention, a maximum yield of liquid hydrocarbon and minimum gasyield is obtained. Moreover, the hydrocarbons obtained under the conditions described have a high degree of unsaturation, a feature not desired by many workers in this art, but

which the present applicant deems a favortherein into a Vvertical stationary gas producer 20. It is immaterial to the present invention what type of gas producer is used for receiving the shale from retort 18, but it has been found convenient that a producer be used having the proportions illustrated in the drawing; that is to say, one having a fuel bed 22 of considerable'height above which is a gas space 24 opening into the lower end of the retort 18. At the lower end of the producer 20 there is illustrated an ash plate 26, and a ram 28 applied by a power cylinder 30 for removing thoroughly spent shale from the lower end of the producer\20. However, the present invention is not limited to any particular type of devices for removing ash or spent shale from the producer. j

Air for maintaining restricted'combustion in the producer 20 and for the formation of roducer gas therein is supplied through the ower Wall of the producer 26 by va pipe 32 passed through said wall. According to the present invention, the air for this purpose is preferably preheated in regenerative furnaces 34, 34. Preferably steam is supplied through furnaces 34, 34 and pipe 32 at the same time with the air in order to assist in the formation of producer gas and` to increase, the production of ammonia in the producer 20,` the ammonia vapor being carried along with the producer gases through the retort 18.

The gases and vapors which pass through the retort 18 comprise the roducer gas formed in the producer 20, the ydrocarbons distilled from the shale in the retort 18, and

the ammonia distilled from the shale in the producer 20. All of these gases and vapors. leave the retort through the chute 16, and

thence pass through a'pipe 36 to a condenser -coil 38.

Condensates and uncondensed gases pass from condenser coil 38 through pipe 40 to condensate tank 42. Liquid hydrocarbons separating out in tank 42 are removed to storage through pipe 44. Uncondensed hydrocarbon vapors, ammonia vapor, and fixed gases pass out of the tank 42 through the pipe 46 and thence to an ammonia scrubber 48. Ammonia liquor isremoved from the bottom of the tank 48 through pipe 50. Light hydrocarbon vapors and fixed gases leave the tank 48 through pipe 52 and pass thence to an oil scrubber 54, in which the vapors and gases are scrubbed by a heavy wash oil for the recovery of light hydrocarbon vapors.

The scrub o`il and the light hydrocarbons contained therein are removed from the bottom of--scrubber 54 by pipe 56. Fixed gas leaves the scrubber 54 by pipe 58 and passes thence through one or the other of branch pipes 60, 60 through the lower wall of one or the other of the regenerative furnaces 34 pre viously mentioned-,according to which one is being heated at the time. The gas coming through pipe 58 carries a considerable portion 4 -of combustible material and this is burned in the regenerative furnaces-34 by means of air supplied through pipes 62, 62 the products of combustion passing in contact with checker work 64, 64 within the furnaces 34. While combustlon is being maintained in one of the furnaces 34 the hot products of combustion pass upwardly through checker-work 64, thus heating the checker' work, ,and pass out through one of the valved pipes 66, 66. At

the same time air passes through the other furnace 34`to be preheated and the heated air then passes through the pipe 32 into the producer, pipe 32 leading from the upper portions of the furnaces 34. The checker work in furnaces 34 is heated alternately and the' combustible gas from pipe 58 is diverted by means of valves 68, 68 in pipes 60 to the other 'furnace 34 and the air entering the highly will be turned by the o erators to force the air and gas streams to t e the desired courses as described above. Also, while these various valves are illustrated merely as h and vvalves they may be any of the approved types of hand or automatically operated valves.

In general, more combustible gas will be made than will be needed in the re enerator furnaces 34 and thi-s excess gas may e led off through pipe 76 for use outside of the system herein described.

It will be seen that in operating accordin to the present invention, the sensible heat o the gas from the producer itself is suflicient to drive ofi' all the liquefiable hydrocarbons from the oil shale and that no gas or other fuel need be burned for this purpose, aside from the carbon in the shale which is gasified in producer 20. Moreover, unless the shale is below the average in richness an excess gas is produced which may be usedlfor operating gas engines or in furnaces as desired.

It is emphasized that, according to the present invention, no heat is supplied to the" rotary retort except the sensible heat of the producer gases. The heatin of the shale is thus very uniform and gra ual, and much more so than if heat were supplied to .the

Having .thus described my invention, I

s claim: 

